This invention relates to a method for manufacturing metal housing or control-component parts having clear plastic indicator inserts.
In comparison to housing or control-component parts made of plastic, metal housing or control-component parts improve the appearance and the readability of various control devices in vehicles, such as navigation systems or heat adjustment systems, lighting devices, etc.
The ATZ-Automobiltechnische Zeitschrift (Journal of Automotive Technology) of December 1998, no. 12, p. 879 discloses one such example. It is stated therein that even during development of a climate regulation system, design, or aesthetics, plays an important role. The system described therein provides for each of two rotary switches for temperature adjustment to be backed with a forged aluminum ring into which optical light guides are integrated for nighttime operation.
In the illustration of a control element backed with aluminum rings shown therein, the optical light guides are in one instance integrated into the rings to be visible as symbols, as are also other symbols positioned on the push buttons. In comparison to the symbols on the rings, those on the push buttons clearly show xe2x80x9cislandsxe2x80x9d within the symbols that are not transparent.
These islands are the reason that such symbols are not placed on metal housings or control-component parts, because during manufacture of recesses to be filled with transparent plastic these islands would fall out.
It is an object of this invention to provide steps for a method of manufacturing such metal housing or control-component parts which makes possible creation of symbols having islands.
According to principles of this invention, a housing and control-component part is manufactured as a forged or cast blank. A recess is then formed therein for receiving an indicator insert using a stamping die in a stamping device, while also causing a protrusion on a back wall surface, in the stamping direction, of the part. The recess is then constricted by making a peeled protrusion on peripheral walls defining the recess. The transparent plastic is then injected into the recess. A back wall surface and the protrusion is then ablated by a fixed thickness amount, which results in exposure of the recess and the transparent plastic at the back wall. Advantageous additional steps are also described herein.
The appearances of metal housing and control-component parts manufactured by this method are improved.